1. Field of the Invention
The invention relates to a camera shake correction apparatus.
2. Description of the Related Art
Known camera shake correction apparatuses suppress image blurring produced in images due to camera shaking caused by movement of lenses serving as optical members and imaging devices serving as imaging members. Camera shake correction apparatuses of this type include known apparatuses having a structure in which a movable member including an optical member or an imaging member is moved with respect to a fixed member with a VCM (voice coil motor) using a coil and a magnet.
Camera shake correction apparatuses are required to control the position of the movable member with high accuracy. To achieve the control, the apparatuses are required to detect the position of the movable member with high accuracy. Known camera shake correction apparatuses are formed of a combination of a position detecting magnet and a magnetic flux detection element such as a Hall element. In recent years, camera shake correction apparatuses including a magnet, both serving as a magnet for detecting the position of the movable member and a magnet for driving the movable member, have been presented size reduction of the camera shake correction apparatuses. In the case of adopting the structure in which a magnet serves as both a magnet for detecting the movable member and a magnet for detecting the position of the movable member, the magnetic flux detection element may detect not only the magnetic flux based on the magnet for driving the movable member (for detecting the position), but also the magnetic flux based on the coil disposed in the vicinity thereof. When the magnetic flux based on the coil is detected by the magnetic flux detection element, the magnetic flux detection element outputs a false position signal. Such a false position signal causes a significant deterioration in position control accuracy.
To prevent such deterioration, the drive control apparatus in Jpn. Pat. Appln. KOKAI Pub. No. 10-62676 discloses a structure of estimating a magnetic flux generated in a coil from a current flowing through the coil to cancel an influence of a false position signal, estimating a false position signal from the estimated magnetic flux, and performing feedback control of the current flowing through the coil to cancel the influence the estimated false position signal.